Epidemiology of gestational trophoblastic diseases.

The epidemiology of gestational trophoblastic diseases is unclear. Problems with collection and interpretation of differing data abound. Hydatidiform mole (HM) is associated with abnormal gametogenesis and/or fertilization. This is further influenced by age, ethnicity and a prior history of an HM suggesting a genetic basis for its aetiology. Whilst a prior HM is significant in the development of trophoblastic neoplasia there is no clear explanation for the development of gestational trophoblastic neoplasia in association with a normal gestation. The development and improvements in suction curettage, termination of pregnancy, contraceptive techniques, diagnostic imaging and biochemical testing have been associated not only with a fall in the birth rate, but also with a reduction in the incidence of trophoblastic diseases. Future study should examine the mechanism of malignant change in normal and abnormal trophoblast.